1. Field of the Invention
This invention relates to recreational water equipment and, in particular, to a flying ski and method of use therefor.
2. Description of the Related Art and Summary of the Invention
U.S. Pat. Nos. 5,100,354 and 5,249,998 disclose an apparatus known as a flying ski. The flying ski is a device adapted to be towed behind a powered watercraft in a manner similar to a water ski. In contrast to a water ski, however, the rider sits on a seat spaced above the ski board and primarily rides on a blade structure that is spaced below the ski board by a vertical strut. When the ski is in use, the rider, seat and board are above the water surface and the blade structure is submerged below the water surface. The flying ski disclosed in the above-identified patents was a pioneering recreational water device.
While the basic flying ski structure remains highly desirable, a number of significant improvements have been developed. First, beginning riders with low skill levels can find the flying ski relatively difficult to operate and can become frustrated to the point that they do not attempt to use the ski again. Second, advanced riders with high skill levels can find the flying ski too easy to operate and insufficiently challenging. A modification that allows for quick adjustment of the flying ski, so as to alter the difficulty of maneuvering the ski would allow both skilled and novice riders to use the device at the same time. Third, the device is currently adapted only for those people who have full use and control of their lower bodies. An improvement to the device that allowed the flying ski to be used by paraplegics would be desirable. Lastly, the device currently has a safety belt that tends to wear out relatively quickly under the high stresses associated with normal use of the flying ski. A more desirable safety belt design would thus be desirable.
The present invention provides several significant improvements to a flying ski. One aspect of the present invention is a ski that accommodates a variety of rider skill levels by incorporating a mechanism and system that allows the rider to selectively adjust performance characteristics of the ski. In particular, ski stability, lift and maneuverability can be controlled by the rider to accommodate the rider""s particular skill level and the particular challenge that the rider seeks. A second aspect of the present invention is a ski that accommodates paraplegic riders. In particular, the seat of the ski is capable of receiving a back support, which a paraplegic rider can use as a lever to manipulate the orientation of the ski. A third aspect of the present invention is a flying ski having a dramatically improved safety belt.
The original safety belt safely secures the rider to the ski, even in high-impact falls. The original safety belt design was subject to wear, however, due to the tendency of the belt to loosen somewhat upon impact. Earlier efforts to overcome this problem were successful in overcoming the problem of slight loosening, but resulted in a seatbelt that was subject to full release/failure. Given the risks associated with unintended full release during a fall, the original design remained preferred, despite the problem of durability. A new seat belt structure has been developed, however, which yields very little, if at all, during the most extreme impacts associated with normal use of the ski and yet prevents full release upon impact. This improvement assures the safety of the rider, while at the same time increasing the life span of the safety belt.
The improved flying ski must be appreciated in the context of the conditions to which it is subjected and the environment within which it is used. Flying skis can be used to jump over twenty feet in the air. Landing impacts from such jumps are very large. Accordingly, the ski structural configuration must be adapted to withstand these forces. Additionally, it is highly desirable that the ski configuration be adapted to minimize the transfer of these forces to the spine of the rider. Finally, riders of different skill levels will often be riding in the same boat and wish to use the same flying ski. Accordingly, it is highly desirable that the flying ski be easily and reliably adjustable to accommodate the various skill levels. The ski configuration should also require a minimum of parts and disassembly thereof, to avoid the risk of parts falling overboard or being lost.
One aspect of the present invention involves a recreational device that supports a seated human rider while the rider and the device are towed behind a powered watercraft. This recreational device comprises an elongated board having a front end and a back end, a seat, a strut which depends from one end of the board and the seat and defines a plane of symmetry, and a blade assembly secured to the strut.
The seat extends from the board for supporting the buttocks of the seated rider at a position spaced above the board.
The blade assembly has a front blade and a rear blade connected by a fuselage. The front blade includes a first portion defining a first surface on a first side of the plane of symmetry. The front blade also includes a second portion defining a second surface on a second side of the plane of symmetry. The first surface and the second surface direct water toward the plane of symmetry upon landing of the front blade on water.
The front blade has a leading edge and the rear blade has a first edge and a second edge. The rear blade is mountable on the fuselage in a first position wherein the first edge defines a trailing edge of the blade assembly. The rear blade is mountable on the fuselage in a second position wherein the second edge defines a trailing edge of the blade assembly. In one embodiment, the greatest perpendicular distance between the leading edge and the first edge when the rear blade is in the first position is longer than the greatest perpendicular distance between the leading edge and the trailing edge when the rear blade is in the second position.
The rear blade may include a first portion defining a first surface on a first side of the plane of symmetry and a second portion defining a second surface on a second side of the plane of symmetry wherein the first surface and the second surface directed water away from the plane of symmetry upon landing of the rear blade on water.
The front blade may further comprise a first depending fin on the first side of the plane of symmetry at a first outer side of the front blade and a second depending fin on the second side of the plane of symmetry at a second outer side of the front blade. These first and second fins may be angled toward the plane of symmetry from front to back.
The front blade may further comprise a third portion which defines a third surface on the first side of the plane of symmetry which directs water away from the plane of symmetry upon landing of the front blade on water as well as a fourth portion which defines a fourth surface on the second side of the plane of symmetry which directs water away from the plane of symmetry upon landing of the front blade on water.
In accordance with the present invention, the front blade may have an upper surface that is curved such that the pressure exerted on said front blade from above is lower than the pressure exerted on the front blade from below.
The rear blade may include a first upwardly curved portion defining a first surface on a first side of the plane of symmetry and a second upwardly curved portion defining a second surface on a second side of the plane of symmetry. In this embodiment, the first surface and the second surface direct water away from the plane of symmetry upon landing of the rear blade on water.
Another aspect of the present invention also involves a recreational device that supports a seated human rider while the rider and the device are towed behind a powered watercraft. This recreational device comprises an elongated board having a front end and a back end, a seat, a strut depending from either the board or the seat and defining a plane of symmetry, and a blade assembly secured to the strut.
The seat extends from the board and supports the buttocks of the seated rider at a position spaced above the board.
At least a portion of the strut is submerged underwater when the device is in use.
The blade assembly has a front blade and a rear blade connected by a fuselage. The front blade has a leading edge and the rear blade has a first edge and a second edge. The rear blade is mountable on the fuselage in a first position wherein the first edge defines a trailing edge of the blade assembly. The rear blade is mountable on the fuselage in a second position wherein the second edge defines a trailing edge of the blade assembly. The greatest perpendicular distance between the leading edge and the first edge when the rear blade is in the first position is longer than the greatest perpendicular distance between the leading edge and the trailing edge when the rear blade is in the second position.
The recreational device may further comprise a blade support mounted between the fuselage and the rear blade. The blade support has a first position in which the blade support cooperates with the fuselage to position the rear blade so as to have a first angle of attack. The blade support has a second position in which the blade support cooperates with the fuselage to position the rear blade so as to have a second angle of attack. A fastener may selectively secure both the rear blade and the blade support in a fixed position.
Another aspect of the present invention involves a kit which can be assembled to form a recreational device that supports a seated human rider while the rider and the device are towed behind a powered watercraft. The kit comprises an elongated board having a front end and a back end, a seat, a strut which is securable to one of the board and the seat and which defines a plane of symmetry, a blade assembly, and a plurality of blade supports.
The seat extends from the board for supporting the buttocks of the seated rider at a position spaced above the board.
The blade assembly is securable to the strut. The blade assembly has a front blade and a rear blade connected by a fuselage. The front blade has a leading edge and the rear blade has a first edge and a second edge. The rear blade is mountable on the fuselage in a first position wherein the first edge defines a trailing edge of the blade assembly. The rear blade is mountable on the fuselage in a second position wherein the second edge defines a trailing edge of the blade assembly. The greatest perpendicular distance between the leading edge and the first edge when the rear blade is in the first position is longer than the greatest perpendicular distance between the leading edge and the trailing edge when the rear blade is in the second position.
Each of the blade supports are alternatively mountable between the fuselage and the rear blade. Each of the plurality of blade supports are sized and shaped to cooperate with the fuselage to position the rear blade so as to have an angle of attack.
Another embodiment of the invention is directed to a blade for use with a flying ski type recreational device that supports a seated human rider while the rider and the device are towed behind a powered watercraft. The blade defines a plane of symmetry and includes a first portion defining a first surface on a first side of the plane of symmetry and a second portion defining a second surface on a second side of the plane of symmetry. The first surface and the second surface direct water toward the plane of symmetry upon landing of the blade on water.
This embodiment includes a first depending fin on the first side of said plane of symmetry at a first outer side of the blade as well as a second depending fin on the second side of the plane of symmetry at a second outer side of the blade.
The first and second fins can be angled toward the plane of symmetry from front to back.
The blade may further comprises a third portion which defines a third surface on the first side of the plane of symmetry which directs water away from the plane of symmetry upon landing of the blade on water as well as a fourth portion which defines a fourth surface on the second side of the plane of symmetry which also directs water away from the plane of symmetry upon landing of the blade on water.
This blade may define between 69 and 114 square inches. Alternatively, this blade may define between 82 and 101 square inches.
Another aspect of the invention involves a method of varying the attack angle of a planing blade for use with a flying ski type recreational device that supports a seated human rider while the rider and the device are towed behind a powered watercraft. The method comprises providing a fuselage that removably attaches to any one of a plurality of rear planing blades and selecting one rear planing blade and attaching the selected rear planing blade to the fuselage.
The step of selecting one rear planing blade may include selecting one rear planing blade with a generally planar surface or one with a curved rear planing blade. A curved rear planing blade that has a pair of spaced apart upswept wings may be selected. The curved rear planing blade may be detached from the fuselage and the orientation of the curved rear planing blade reversed so that the curved rear planing blade has a pair of spaced apart frontswept wings. The rear planing blade is then reattached to the fuselage.
The method also may comprise the steps of detaching the rear planing blade from the fuselage, placing a blade support in a cut-out formed in the fuselage and reattaching the rear planing blade to the fuselage.
The apparatus, in any of the embodiments described so far, may also comprise a detachable back support. The back support is constructed from two principal pieces, the first being a flat rectangular sheet of material having a thickness that is much less than either its length or its width. This piece is bent at a ninety-degree angle along an axis that lies perpendicular to the longitudinal axis of the rectangular sheet, thus forming a horizontal section and a vertical section. The vertical section is preferably approximately two and one-half times the length of the horizontal section.
The second principal piece is a spine, also xe2x80x9cLxe2x80x9d-shaped, and attached to the back of the vertical segment and the underside of the horizontal segment. The spine has a significant thickness in the direction perpendicular to the rider""s back, so that the spine imparts a substantial amount of rigidity to the seat back. This rigidity ensures that the seat back will act as a lever, enabling the rider to alter the angle of attack of the planing blades by exerting pressure on the upper end of the seat back. The rider applies this pressure by raising or lowering his hands.
A further aspect is an improved safety belt. The belt has two straps, each having a free end, and a stationary end that is secured to the seat of the flying ski. The xe2x80x9cfemalexe2x80x9d strap is fitted with a clamp at its mating end, into which the xe2x80x9cmalexe2x80x9d strap is inserted when the belt is fastened. To adjust the fit of the belt, the male strap is pulled through the clamp until the desired tightness is reached. The clamp is then closed, allowing the teeth of the clamp to engage the male strap and prevent the male and female straps from moving relative to one another.
Since the effectiveness of the belt is dependent upon the strength of the engagement between the clamp and the male strap, it is desirable to provide a connection that will not yield, even when subjected to extreme tensile force. In order to increase the strength of the connection, the frictional force generated by the interaction of the clamp and the strap must be increased. This frictional force is equal to the product of the normal force and the coefficient of static friction between the two straps. Therefore, in order to increase the frictional force present, one of these two components must be increased.
Preferably the coefficient of static friction between the clamp and the male strap is increased by providing, on the surface of the strap, a material comprised of a multitude of tightly packed loop fibers. The loops engage the teeth of the clamp and act as anchors, preventing the teeth from advancing along the surface of the strap.
The apparatus, in any of the embodiments described so far, may also comprise a padded safety belt. The belt is preferably substantially identical to the improved safety belt described above, and includes first and second padded strips attached to an underside. The strips are substantially rectangular lengths of resilient material covered by a durable fabric. The strips are preferably releasably attached to the belt with a hook and loop fastener. Alternatively, the strips may be secured to the belt with straps that wrap around the belt, such that the strips are slidable along the belt. The strips provide a soft interface between the rider and the belt, thus increasing the rider""s comfort and enabling the rider to enjoy using the flying ski for longer periods of time.
Further aspects, features, and advantages will become apparent from the detailed description of the preferred embodiments that follows.